The present invention relates to flashlights, and, more particularly, to a printed circuit board (xe2x80x9cPCBxe2x80x9d) for mounting a plurality of LEDs within.
Flashlights that use one or more LEDs as a light source typically include a housing for a portable power source (e.g., batteries) and a switch to connect and disconnect the LEDs and the power source to turn the flashlight on and off. In U.S. Pat. No. 6,168,288 to St. Claire entitled FLASHLIGHT WITH LIGHT EMITTING DIODES, which is commonly assigned, and which is incorporated fully herein by reference, an LED flashlight is disclosed.
The brightness of an LED flashlight relates to the number of LEDs. Previously, the number of LEDs mountable within an LED flashlight was limited by the structure on which the LEDs were mounted and the arrangement of the LEDs on that structure. For example, in the U.S. Pat. No. 6,168,288 to St. Claire mentioned above, the LEDs are mounted on a printed circuit board (PCB) having an inner conductor and an outer conductor with the terminals of each LED connected to a different conductor. This arrangement effectively limits the number of LEDs that can be mounted on the PCB.
One of the factors that limits the number of LEDs that can be mounted on a PCB is the distance that the terminals of individual LEDs have to travel to connect the LED to the conductors on the PCB. On a PCB having only an inner conductor and an outer conductor, as the number of LEDs mounted on the PCB increases, the positioning of some of the LEDs will require one or both of their terminals to travel greater distances to reach the conductors. Greater distances traveled by the terminals of the LEDs complicates the manufacturing process and may increase the flashlight""s susceptibility to shorts and open circuits, thereby interfering with the operation of the LED flashlight.
Accordingly, a need exists for a mounting structure for mounting LEDs within an LED flashlight that addresses the problems and limitations discussed above. The present invention fulfills this need among others.
The present invention provides for a PCB for use in an LED flashlight which overcomes the aforementioned problems by positioning conductors on the surface of a circuit board to allow a plurality of LEDs to be positioned on the board with each LED substantially adjacent to the conductors. In addition, a flashlight is provided in which the PCB of the present invention may be used.
The PCB of the present invention includes a circuit board having a first surface and a second surface opposite the first surface. On the first surface is a first conductor having a first section and at least a second section at least partially surrounding the first section. Also on the first surface is a second conductor having a first section between the first and second sections of the first conductor, the second conductor being electrically isolated from the first conductor. In one preferred embodiment, the second conductor further includes a second section at least partially surrounding the second section of the first conductor.
The PCB of the present invention is configured to receive a plurality of LEDs. Each of the LEDs has a pair of terminals that may be electrically connected to a separate one of the first and second conductors of the PCB.
The preferred flashlight of the present invention includes a housing having first and second ends and is configured for receiving a power source. A circuit board having a first surface and a second surface opposite the first surface is preferably positioned adjacent to the second end of the housing. The circuit board has a first conductor having a first section and at least a second section at least partially surrounding the first section and a second conductor having a first section between the first and second sections of the first conductor, the second conductor being electrically isolated from the first conductor. A plurality of LEDs, each having a pair of terminals, are electrically connected to the first and second conductors. A cap is preferably mounted on the second end of the housing and a switch is preferably provided to electrically connect and disconnect at least one of the first and second conductors and the power source when the power source is in the housing.